The separation of Wikstroemia from the following genus, Daphne, is problematic. Features such as leaf arrangement, inflorescence type, and flower color are all clearly paralleled within the two genera and are of no diagnostic value, although they are mentioned in most keys to these genera. In most cases, the nature of the hypogynal disk is diagnostic, but even here there are species where the interpretation of the structure of the disk is difficult. For example, the distinction between the lateral ± square disk seen in several species of Daphne and species of Wikstroemia with a single large disk scale, or species of Wikstroemia in which the disk scales are connected by a narrow annulus, or species of Daphne with very deeply divided disks makes the division seem rather arbitrary, such that there must be a good case for combining these two genera, as was done by Halda (Genus Daphne. 2001). A review of generic delimitations in the family based on molecular data would be very desirable.

Wikstroemia ganpi (Siebold & Zuccarini) Maximowicz was indicated by Halda (loc. cit.: 158, as Daphne ganpi (Siebold & Zuccarini) Halda) to occur in Taiwan, but this species has not been recorded by botanists from Taiwan, and the basis of the record was not indicated.